Preheat the oven to 350° F. Lightly grease a large casserole dish.
Add pears and blackberries to the casserole dish. Toss with 3 tablespoons of sugar, cornstarch, and lemon juice, making sure all the fruit is evenly coated.
In a medium mixing bowl, combine flour, baking powder, and remaining sugar. Whisk to combine. Pour in the butter, milk, vanilla, and salt. Mix well until a thick dough forms.
Drop the cobbler dough by spoonful’s on top of the fruit and place in the oven to bake until the fruit is bubbling and the cobbler is nicely golden-brown, approximately 25-30 minutes.
Serve with some vanilla ice-cream or a dollop of whipped cream. Enjoy!